On paper, the biggest mismatch in the 49ers-Eagles game Sunday isn't hard to spot.

The Niners' wide receivers versus the Eagles' cornerbacks?

Oh. Boy.

San Francisco's wideouts have been largely invisible in the first three games as part of the NFL's 32nd-ranked offense. In contrast, the Eagles' stable of cornerbacks is the most high-profile in the league: Nnamdi Asomugha, Asante Samuel and Dominique Rodgers-Cromartie have combined for eight Pro Bowl berths.

"I'm always excited about a challenge; that's why you play the sport, for the competition," Morgan said. "Anybody that thinks they're a good wide receiver wants to go against the best DBs - they're the best DBs. We love the challenge. We're just going to use great technique and do what we do. We make plays, too. We're not going to back down from anybody."

Which actually might be a smart approach, considering the Eagles have allowed eight receiving touchdowns this year, tied for most in the league.

Said Crabtree of facing the Eagles' talented trio, "It's like that every week. That's why it's the NFL. The best of the best."

In examining the NFL's best, though, it takes some serious scrolling to find a 49ers wide receiver. San Francisco's wideouts have combined for 20 catches, 206 yards and one touchdown. Seven NFL wideouts have as many catches as the Niners' entire corps and 21 have more yards.

The reasons for their irrelevance are tied to some of the same problems that have plagued the NFL's lowest-ranked offense as a whole. Topping the list of maladies is an offensive line that has allowed 11 sacks over the past two weeks.

Routinely under pressure, quarterback Alex Smith hasn't always had time to look downfield. In addition, his top two wide-receiving targets, Crabtree and Braylon Edwards, have dealt with injuries and have combined to finish two games this season.

Crabtree (foot) has been limited in practice this week but has declared that he's healthy. Edwards will miss his second straight game after undergoing surgery for a torn meniscus less than two weeks ago.

Even at less than full strength, Morgan expressed confidence the wideouts will perform better with a little polish.

"There have just been too many miscues in the offense," Morgan said. "Small things - protection issues or miscommunication between the quarterback and running back or the quarterback and the receiver - just little things, minor details that can be fixed. And that's what keeps you excited, because you know they can be fixed."

Offensive coordinator Greg Roman said the wideouts have been heavily involved in the game plans, but in last week's 13-8 win over Cincinnati, for example, he said the Niners looked to tight end Vernon Davis (eight catches, 114 yards) "just based on what the defense was doing."

This week, the primary focus might not be on Davis or the wideouts.

The Eagles' 30th-ranked run defense has been gouged for 131.3 yards per game and has allowed 4.9 yards per rush, the league's fourth-worst average.

Combine those numbers with those cornerbacks, and it's possible the Niners' wide receivers might be waiting at least one more week to emerge from obscurity.